Electroconductive substrates are well known in various industries especially the transportation industry. Probably the best known application is as a window with a defogger element for use on automobiles, airplanes and display freezers. These substrates have also been used on CRT screens and other electronic instruments to control static electricity and errant electrical emissions, as well as flat heaters for industrial and commercial uses.
Generally, the substrates are formed of one or more transparent layers of glass or plastic on at least one surface of which is placed a conductive layer or grid pattern formed of wire, wire mesh, or metal based coatings, such as lacquers paints, or inks. This layer is generally covered by a protective covering such as an adhesive layer and a layer of glass or plastic which are laminated together to form an electroconductive window. Such a window construction is taught by U.S. Pat. No. 4,102,722.
A busbar assembly is formed at the edges of the conductive layer to provide a conductive path through which electricity may flow to or from the conductive layer. These busbars have been formed of conductive coatings which are sintered in place or metallic strips which are soldered in place to the conductive layer and an electrical lead which is separately and sequently soldered on the busbar.
These approaches, especially soldering are time consuming, labor intensive and often result in thermal cracking or spawling of the glass or melting of the plastic. Further, the approaches do not ensure a good contact between the conductive layer and busbar or the busbar and electrical lead, which results in uneven electrical distribution throughout the layer, short circuits or even destruction of the windows. The need has existed for a busbar assembly that was quick and simple to attach, which reduced or eliminated cracking, spawling or melting and which ensured even contact and distribution of electricity to and from the window.